Gas furnace



Aug. 4, 1931. F. E. GRUNWALDT ,3

' GAS FURNACE Filed March 29. 1928 2 Sheets-Sheet 1 W m Ii E W /I W i 1I I 44 HU r u I 21; K r (A I 3 3 6 i 2 W0 ,0 /2 7 i) W 8 (IN g 5 V3 IIH42 fimkmmmur I ATTORNEY Aug. 4, 1931. F. E. GRUNWALDT GAS FURNAG E 2Sheets-Sheet Filed March 29, 1928 f'rankfi am ufir ATTORNEY ID :Theobject ofthe invention'is to Patented Aug. 4, 1931.

'GRUnwA nT, or, SEATTLE, wnsnmefron ens FURNACE The invention is afurnace that isparticularly adaptable for burning gasin which the Wallof the fire box is corrugated or formed with channels'and a central airheating cham- 23 her-1 is. provided inthe center of the fire boxwithra'conical lower end which deflects the hot gases outward so'thatthey will passupwardthrough the corrugationsor channels in the wallsof'the fire box. 1

furnace,the interiorof which is so" arranged that gas maybe used as fueland at the same time the fuel cost .keptbelow' the average. -Anotherobject of the invention is to proi rfi vide. a gasheating furnace inwhich practically all of the heat unitsinay be extracted from the gas:

. Another ob'ect theinvention is to provide .a heating furnace in whichair isc1r-.

culated through and around the fire box.

Another object of theinventionis to provide a heating furnace inwhichthe wall of the fire box; is provided with corrugations orcomparatively deep channels into which the hot gases are deflected sothat the hot gases; will travel upward through the channels. r Anotherobject of the inventionis to pro- 'vide a, furnace in. which the wall ofthe fire "370 .box' is provided with corrugations: or com-- parativelydeep channels so that the heating surface is considerably multiplied. II i I Anotheriobject of the inventionis to provideacombination ofafirebox having a corrugated wall with a central heating chamber in thecenter of the lire box therebyconsider- I ably multiplying thedirectheating surface.

. Another object of the invention is to provijde means for forminga'joint in the wall of ing to be opened so that the entire interior maybe withdrawn without moving the casing' or the flue connections thereto.

. 'Another ob'ect of the inve t on is to pro- .vide means for connectingthe upper and lower ends of the side walls of channels in the wall of afurnace firebox to permit drainage and expansionwith simplicity.

Another object'of-the invention is to pro vide-i neansfor connecting theside walls of a provide a a furnace casing; which will. permit the cas-'openings.

' Application filed March 29, 192s. Serial 110.265,?70.

furnace casing to the furnace front through I which the; side walls will[be drawn or.

stretched as they are clamped in place.

A further obj ect of the invention is to proi vide meansfor.constructingthe interior of 55 a furnace'so that the gasesfrom theflames will pass upward and be deflected outward 1nto the corrugationsor channels-in thewall of the fire box and then pass downward to a flueopening. I m I I A still furtherobject of the invention is to provide afurnace having a central ainheat- I g ilng chamber witha'conical shapedlower end which is provided with intake passages through the lower end,the cross sectionalarea of which is equal to the cross sectionalareaof Ithe chamber.

And a still further object of the malari II is to provide a gas furnacewhich provides economlcal gasconsumption'and which'is of a simple andeconomical construction,

With these ends in view the invention em I v bodies a furnaceha'ving afire box, with walls havmg corrugations or channels", a central chamberwith a conical shaped lower endhaving passages extending therefromthrough the wall at the lower portion of thefire'box, a

flueextending from the said fire'box,and an outer casing having aslipjoint at the front.

2nd clamp joints at the sides ofthe furnace ront.

' Other features and advantagesofthecin- I .vention will appear from thefollowing (113- y scription, taken in connection withthe draw-v ings,wherein I "Figure 1 is'a vertical cross section showing thefurnace.

I Figure 2 is a similar section "showing the lower portion of thefurnace witha forced I draft air duct entering the rear thereof. i r

Figure 3 is a cross section through the upper part of the furnace online 3 3 of Figure 1. i

' Figure 4 is a similar section showing a por- 9 tion of the fire boxwith a plate'connecting the outer ends of the corrugations. I

Figure 5 is also a similar section showing a fire-box divided intotwo-parts with two. flue in the outer chamber 3 Figure 6 is also asimilar section showing corrugations of a different shape.

Figure 7 is a detail showing the means for connecting the ends of thesides of the ,corrugations to the top and bottom.

Figure 8 is a similar view showing the edge of the plates.

Figure 9 is a detail showing the means of connecting the lower portionof the outer casing to the furnace front.

In the drawings the furnace is shown as it would be made wherein numeral1 indicates the inner air heating chamber, numeral 2 the fire box, andnumeral 3 theouter chamber.

r In the structure shown the inner chamber is formed with a cylindricalcasing 41 having a cone 5 at the lower end, and it understood thatalthough this is shown in a cylindrical'shape it may be oval, square orof any other suitable shape. The cone 5 is provided with passages 6which extend through'the fire box 2 and through the wall 7 which formsthe wall of the lower portion of the fire box 2. At the lower end and atthe front of the fire box 2 is a'passage 8 which connects to the furnacefront 9 and is provided with a door 10 having a ventilator 11 therein.At the rear of the casing is a duct 12 through which a gravity flow ofair will pass into the casing.- A feeder pipe 13 extends through thedoor to a burner as shown'in Figure 1 and the outerend of the feederpipe 13 may be connected by a pipe 14 to any suitable fuel supply. Thefire box extendsupward as a cylinder to the point 15 and at this pointthe "actual wallsof thefire box are corrugated or provided with channels16 and it will be observed that the fiames'and hot gases from the firewill travel upward until they strike the cone 5 and then be deflectedoutward so that they will pass upward through the chan nels 16. Thesechannels may be triangular shaped asshown in Figures 3, 4-, and 5 or ofa rectangular shape as shown. in Figure 6 or of any other suitableshape. It will be noted that onthe opposite side of the walls of thechannels 16are other channels which are inidicatedby the numeral 17whichmay be known as exterior or air channels and the air Wlll passupward through these channels with considerable velocity as the spacebetween the walls of the channels will beheated to a very hightemperature and the air therein will paf'supr-zard. At the same time theair in the chamber 1 will also pass upward with considerable velocity asthis chamber will also be heated to a very high temperature and it willtherefore be possible to heat a large quantity of air to a very hightemperature in a very short time so that a comparatively small furnacewill have considerable capacity. The furnace will also havea maximumefficiency as the area of the fire box is comparatively small owing tothe fact that the fire box is distributed through a plurality ofvertical chambers so that the surface area of the fire box walls is verylarge and as the exterior of these walls form direct heating surfaceswith the air to be heated coming into direct contact with them, aheating surface of a very large area in comparison with the size of thefurnace is provided.

The burner on the pipe 13 may be positioned as shown in Figure 1 so thatthe gas will be ignited thereby forming a combustion chamber at thepoint 18 which will be directly below the cone 5 and the cone 5 willspread the flames and hot gases equally so that they will pass upwardthrough the channels 16 and then downward through openings 19 in thewalls of two of the channels into a box 20 formed between the channelsand from the box '20 the gases may escape through a pipe 21 to a stack;It will be noted that the hot gases will pass upward on the interior oraround the casing 4 and as this space and also the upper ends of thechannels 16 are closed these gases will pass outward and downwardthrough the outer part of the channels 16 and as their only escape isthrough the box 20 at the stack opening, and also as they will be drawnby the stack draft they will find their way to this point and escape tothe stack.

The chamber 3 is enclosedwith a casing having a joint at the front asshown in Figure 3 in which one end of the casing is bent around andunder to form a slot 22 into which the other end 23 will slide and the"outer surface of the ends is provided with removed so that the endswill open and these ends may be, opened to the position indicated by thedotted lines 27 so that the inner part of the furnace may be removedthrough the front of the casing. The lower portion of the casing may beattached to the furnace front 9 by channel shaped clips 28 as shown inFigure 9. The ends of the lower portion fofthecasing which'are indicatedby the numerals 29. are provided with. flanges 30 which will be held. inthe positionshown in dotted lines in Figure 9 and it will be observedthat as a nut 31 on a bolt 32 is tightened it will draw the member 28downward to the position shown'in full lines and this will draw the end29 of the casing to the position shown in full lines also so that thecasing will be drawn into place and rigidlyheld. I

The ends of the plates forming the walls between the channels 16 and 17may be made as shown in Figures 7 and 8 in which the 1 and which formthe walls box and which is beveled so that it will slope downward at theupper end and up.- ward at I the lower end is provided with flanges 34the upper edges of which are horizontal as shown so that the upperends'of the plates which are indicated by the numeral 35 between thechannels 16 and 17 may be crimped'over the edges of the flanges 34 asshown. This will make it possible to form a tight joint without cuttingand bending the ends of the vertical plates or a bevel.

In the structure shown in Figure 2. the lower portion of the furnace isprovided with a forced draft intake duct 36 which opens into a chamber37 surrounded by a wall 38 which extends upward to the lower end of thechannels 16 and 17 so that as air is forced'in through this'duct it willpass upward through the'channels 16 and 17 and also through the openings6 in the lower end of the chamber 1.. It is understood thatalthough theforced air duct is shown in this manner it may be arranged in any othersuitable manner and any other suitable connections may be providedbetween the duct and the upper portion of-the'furna'ce.

In the structure shown in Figure .4 the channels 16 and 17 are providedwith an outer covering 39 which may extend continuously around thechannels so that the outer ends of the channels will be closed-therebyforming closed air spaces within the chan-' nels.

In the structure shown in Figure 5 the channels may be divided into twosections with partitions 40 and 41 connecting the innor edges of thechannels to the wall 4 of the chamber, 1 so that the fire box willbedivided into two compartments and each compart ment may be providedwith a vent as indicated by the numerals 42 and 43, In this design thefurnace may be provided with a,

single burner as shown in Figure 1 or with two burners as shown inFigure 5 with each burner under a section of the fire box. It is alsounderstood that the two burners may be used with the structure shown inFigure 1 or with any ofthe other designs as may be desired.

A moisture pan as indicated by the numeral 44 may be provided in thewall of the upper part of the casing as shown in Figi ure 1.

It'will be understood that changes may be v made in the constructionwithout departing from the spirit of the invention. One of which changesmay be in the general design or shape of any of the parts, another maybein the location or arrangement of the stack connection, another may bein the arrangement or general design of the casing, and still anothermay be in the location or arrangement of the burner. Y

the duct 36 so that it will be forced into The construction will bereadily understood from the foregoing description. To I use the deviceit may be assembled as shown and it will be observed that as the gas ischannels and chamber 1. It will therefore be observed that the furnaceof the highest pos-' sible efficiency will be obtained as the fire boxis limited to a plurality of walls with air contacting the outersurfaces so that the heat will be directly transmitted to the air andthe air currents will pass upward with considerable velocity so' that alarge quantity of air may be rapidly raised to a very high temperature.It will be observed that. with a furnace of this type there is no grateor fire pot and it would be impossible to install a the pot with thistype of construction so that the furnace is only adaptablefor burninggas or the like or for a gas stove. p

Having thusfully described the invention,

what I. claim as new and desire to secureby Letters Patent, is:-" a

inner cylindrical chamber having a conical shaped lower end, anintermediate cylindrical shaped chamber with the portion thereofsurrounding the straight portion of the said inner chamber corrugatedbyforming the wall thereof in a zig zag form, said intermediate chamberhaving an opening at the bottom and in one side with an enclosure aroundthe said opening forming a fire box, comparatively large tubes extendingfrom the conical por- Inafurnace ofthe character described, an

tion of the inner chamber through the walls.

of the said intermediate chamber, the aggregate area of the said tubesbeing substantially equal to the cross section area of the said innerchamber, a jacket surroundi'ng the said intermediate chamber and formingan outer casing to the upper portion of'which connections may be made toconvey the heated air therefrom to remote points, a burner positioneddirectly below the conical portion of the said inner chamber, anda stackconnection boxed in between the corrugations of the said intermediatechamber at the lower end of the said corrugations and connecting to thesaid intermediate chamber through open- 'ings in the walls of the saidcorrugations. I

V I FRANK E. GRUNWALDT.

